1. Field
The present disclosure relates to a semiconductor light emitting device and/or a method of fabricating the same, and more particularly, to a semiconductor light emitting device of which luminescence efficiency is improved by increasing hole injection to an active layer by using a hole injection layer and/or a method of fabricating the same.
2. Description of Related Art
A semiconductor light emitting device (LED), for example, a LED using a Group III-V compound semiconductor such as gallium nitride (GaN), has received a lot of attention in various fields including illumination engineering and display devices due to its superior efficiency for converting electric energy into light, compared to an incandescent light or a fluorescent light. In illumination engineering fields, a white light emitting device may be used. Currently, a white light may be formed by combining a phosphor with a blue light emitting device.
In such white light emitting devices, luminescence efficiency may be an important factor for evaluating the converted light energy against supplied electric energy. Generally, luminescence efficiency may significantly deteriorate as a current increases in a blue light emitting device. The phenomenon is referred to as efficiency droop. Various research is currently being made to address the efficiency droop.
Efficiency droop of a blue light emitting device may occur due to various causes. For example, known causes for efficiency droop include high defect densities due to a lattice mismatch between GaN and a substrate, relatively low mobility of holes, and overflow of electrons. Particularly, in a multiple quantum well (MQW) structure including a plurality of quantum wells (e.g., from 5 to 10), light may be mainly emitted only at quantum wells close to p-GaN due to low mobility of holes.